Joint Decoupling Optimization of Frequency Offsets and Array Elements for Frequency Diverse Arrays

Frequency diverse array (FDA) has a distance‐angle–dependent beam direction map, which has a greater application advantage than phased array. However, due to the distance‐angle coupling and periodicity of its beam direction map, it makes the parameter information of the target obtained through FDA have ambiguous phenomena. Currently, researchers mostly use different types of frequency offsets, array element arrangement, and optimized parameters to eliminate the coupling and periodicity, but the effect is poor and does not consider the balance between the main flap width, side flaps, and gate flaps. We introduce an improved distributed array with two ends transmitting and middle receiving into the FDA‐MIMO radar and propose a new distance‐angle decoupled beam formation method to eliminate the coupling and periodicity of the FDA beam. The method utilizes the NSGA‐II algorithm to jointly optimize the frequency offset increment and array element layout to achieve complete decoupling of the distance‐angle dimension and spot beam focusing and significantly suppresses the sidelobes and eliminates the grating flaps, providing flexible and adjustable beam characteristics. Simulation results demonstrate the effectiveness of this scheme.